Prevalence, genetic diversity of and factors associated with ESBL-producing Enterobacterales carriage in residents of French nursing homes.

OBJECTIVE:To determine the prevalence and genotypic characteristics of extended-spectrum β-lactamase-producing Enterobacterales (ESBLE) and carbapenemase-producing Enterobacterales (CPE) in nursing homes (NHs) in a French region. Risk factors associated with their carriage were also investigated. METHODS:A point-prevalence survey was proposed from November 2017 to June 2018 to NHs in the study region. Volunteer residents were screened for ESBLE and CPE carriage. Escherichia coli and Klebsiella pneumoniae isolates were genotyped using multi-locus sequence typing, pulsed-field gel electrophoresis (PFGE) and phylogrouping (for E. coli alone). Collective and individual data were analysed by random-effects logistic regression. RESULTS:The study was conducted in 18 NHs and included 262 patients. Fifty-two patients (19.8%) carried at least one ESBLE, corresponding to 56 isolates (42 E. coli, 11 K. pneumoniae and three others), while no CPE was detected. The majority (27/42) of ESBL E. coli belonged to phylogroup B2, and ST131 was over-represented in this subset (21/27). PFGE analysis revealed ST131 cross-transmission within NHs. Regarding ESBL K. pneumoniae, nine of 11 isolates belonged to ST663, and PFGE suggested diffusion of the clone in six NHs. Significant individual risk factors for colonization by ESBLE were: use of a shared bathroom, previous antibiotic use and recent history of hospitalization. Significant collective protective factors were proper compliance with glove use and support of the NH by a healthcare facility. CONCLUSION:This study shows that NHs in the study region are an important reservoir of ESBLE, whereas no residents were CPE carriers. The control of ESBLE in NHs should focus on antibiotic stewardship and excreta management policies.